Imagine trying to rewind the clock and start your life anew, perhaps by moving to a new country or starting a new career. You would still be constrained by your past experiences and your existing biases, skills and knowledge. History is difficult to shake off, and lost potential is not easily regained. This is a lesson that applies not just to our life choices, but to stem cell research too.

Over the last four years, scientists have made great advances in reprogramming specialised adult cells into stem-like ones. By turning back the clock, they can once again imbue the potential to produce any of the various cells in the human body. It’s the equivalent of erasing a person’s past and having